Common test used on heart patients who need defibrillator implants unnecessary, study says

May 8, 2014

New research from McMaster University suggests that a commonly performed test during certain types of heart surgery is not helpful and possibly harmful.

The testing procedure, known as defibrillator testing (DT), is commonly used on people who require implantable cardioverter-defibrillators (ICDs) to prevent sudden cardiac death. It involves putting the patient into cardiac arrest to determine if the defibrillator can first recognize, then successfully shock the patient back into a normal heart rhythm. It requires the use of general anesthesia and is associated with uncommon but potentially life-threatening complications.

"As with many things in medicine, technology evolves and our knowledge grows and we have presented good evidence that the DT, which has been in use for nearly 30 years, is no longer necessary," says lead author Jeff Healey, associate professor of medicine, in the Michael G. DeGroote School of Medicine at McMaster University.

"Without the testing we can save a significant amount of time, money and more importantly, avoid potentially serious complications in patients who are receiving an ICD," he says

Similar to a pacemaker, an ICD is a small battery-powered electrical impulse generator meant as a permanent safeguard against sudden arrhythmias. Each year, about 300,000 worldwide receive an ICD. Of these, approximately 70 per cent undergo the routine defibrillation testing that often leads to potential complications including possible harm from ICD shocks, says Healey.

"Over the last 10 years, there has been an important shift in practice around the world towards ICD implantation without the test. However, until now, there has been no scientific evidence to support this change in practice. Our study now provides clear and robust evidence to guide practice."

To test the procedure, Healey initiated a randomized trial, called the "Shockless IMPLant Evaluation (SIMPLE)" study. It is the largest randomized clinical trial of ICD recipients to date, involving a cohort of 2,500 patients worldwide.

The trial compared standard DT in a patient to those who do not have the testing performed and revealed that those who received ICDs without DT did as well as those who underwent the standard testing.

Related Stories

Improved patient education and ongoing psychological support will help people cope with the psychological distress of having an implanted defibrillator, according to a scientific statement from the American Heart Association.

Patients who received an implantable heart defibrillator in everyday practice had survival benefits on par with those who received the same devices in carefully controlled clinical trials, according to a new study that highlights ...

A new type of defibrillator implanted under the skin can detect dangerously abnormal heart rhythms and deliver shocks to restore a normal heartbeat without wires touching the heart, according to research in the American Heart ...

Patients in mild heart failure who receive a specialized pacemaker known as cardiac resynchronization therapy with a defibrillator (CRT-D) may live longer than those implanted with a traditional implantable cardioverter defibrillator ...

A researcher at the Cardiovascular Institute (CVI) at Rhode Island, The Miriam and Newport hospitals has found that a simple blood test can predict a person's risk for sudden cardiac death, enabling physicians to more quickly ...

Recommended for you

Researchers at the University of California, Berkeley, in collaboration with scientists at the Gladstone Institutes, have developed a template for growing beating cardiac tissue from stem cells, creating a system that could ...

Researchers at the University of Cambridge, in collaboration with the University of Edinburgh, have shown how a radioactive agent developed in the 1960s to detect bone cancer can be re-purposed to highlight the build-up ...

Researchers have long had reason to hope that blocking the flow of calcium into the mitochondria of heart and brain cells could be one way to prevent damage caused by heart attacks and strokes. But in a study of mice engineered ...

A protein that targets the effects of a faulty gene could offer the first treatment targeting the major genetic cause of Pulmonary Arterial Hypertension (PAH), according to research funded by the British Heart Foundation ...